Only if you join early enough for the early exercise cost to be low. Anyone that joined after the first few years probably won’t be able to or want to pay the upfront cost for early exercising.
Early startup employees are typically granted stock options. Stock options can be exercised, and the spread is taxed. Very early stage employees typically opt to do a 83b and early exercise. In this case the tax is due right then, but because the strike price is low and spread is nominally 0, the overall cost is low as well.
If you join later when your strike price is already high, it’s not financially viable for most to early exercise.